The present invention is generally related to phacoemulsification handpieces for the removal of cataract lens from an eye, and is more particularly related to sleeve apparatus for phacoemulsification handpiece.
A well known method for the removal of a cataract through a surgical incision in the eye is now phacoemulsification. A handpiece for phacoemulsification generally includes an ultrasonic generator which is attached to a hollow needle. Vibration of the needle by the generator is used to emulsify lens tissue and aspiration of the emulsified lens tissue, and is effected through a lumen in the needle.
The needle is surrounded by a sleeve when inserted through an incision in the eye, and a needle tip engages and emulsifies the cataract while suction is applied to the needle lumen to withdraw the emulsified cataract through the needle and out of the eye.
The infusion sleeve is typically made from silicone, which provides a desired flexibility for fluid sealing at the handpiece interface and with eye tissue. The sleeve therefore protects the wound through which the needle is passed from contacting the needle which can become heated. Additionally, the sleeve establishes an annular passage around the needle for providing irrigation fluid to the eye while at the same time cooling the needle. It is important that the sleeve tip be sufficiently rigid to withstand insertion through the wound entry into the eye.
The present invention is directed to an infusion sleeve, which provides enhanced rigidity to facilitate insertion into an eye wound. In addition, fluid flow with the irrigation fluid is controlled by the sleeve in order to minimize fluid flow between the sleeve tip and the phacoemulsificaiton needle.
Sleeve apparatus in accordance with the present invention for a phacoemulsificaiton/irrigation and aspiration handpiece, generally includes an elongate sleeve, having a proximal and a distal end. The sleeve has a larger diameter than a needle passing therethrough and accordingly establishes an annular passage around the needle, which enables irrigation fluid to flow therethrough the annular passage and a cornea/sclera wound. Thus, the irrigation fluid passing over the needle provides cooling.
The elongate sleeve includes a hub disposed at the proximal end for enabling the attachment of the sleeve to the handpiece. A port, disposed proximate the distal, is provided for introducing the irrigation fluid into the eye.
An internal circumferential berm is disposed between the port and the distal end in order to reduce the flow of irritation fluid therepast, provide rigidity to the proximal end and concomitantly provide limited contact with the needle in order to reduce thermal transfer therebetween.
More particularly, the berm has a length measured along a longitudinal axis of the sleeve, which is less than a distance between the port and the distal end. This reduced distance is provided to minimize contact and reduce heat transfer. The berm may have a length which is approximately equal to a distance between the port and the distal end. This may be provided in order to further limit the amount of fluid flow therepast and enhance the flow of fluid through the port for irrigation purposes.
Alternately, the sleeve apparatus in accordance with the present invention, may include an elongate sleeve, having a hub disposed at the proximal end for enabling attachment of the sleeve to the handpiece, and a port disposed proximate the distal end in fluid communication with the annular passage for introducing the irrigation fluid to the eye. The elongate sleeve may include a first diameter between the proximal end and the port and a second diameter between the port and the distal end with the second diameter being smaller that the first diameter.
In this instance, the second diameter is sized for reducing flow of irrigation fluid therepast in order to increase flow of irrigation fluid through the port. For example, the second diameter may have a length, measured along the longitudinal axis of the sleeve, which is less than a distance between the port and the distal end in order to reduce thermal transfer between the sleeve and needle.
Alternatively considered, the elongate sleeve may be provided with a first wall thickness between the proximal end and the port and a second wall thickness between the port and the distal end with the second wall thickness being greater that the first wall thickness.